Garrity D B, Zahler S A
Section of Genetics and Development, Cornell University, Ithaca, New York 14853.
Genetics. 1994 Jul;137(3):627-36. doi: 10.1093/genetics/137.3.627.
It has been proposed that uncharged tRNA molecules may act as positive regulatory factors to control the expression of a number of operons in Bacillus subtilis and related bacteria by interacting with leader sequences to cause antitermination. In this study we report the isolation and characterization of regulatory mutations that modify one of the tRNA molecules predicted to have such a regulatory role. Three different alleles of the B. subtilis leucine tRNA gene leuG were found that resulted in higher expression of the ilv-leu biosynthetic operon. Each resulted in a base change in the D-loop of the leucine tRNA molecule with the anticodon 5'-GAG-3' (leucine tRNAGAG). Experiments with strains that are diploid for mutant and wild-type alleles suggested that both charged and uncharged tRNA molecules may interact with leader sequences to control expression of the operon.
有人提出，不带电荷的tRNA分子可能作为正调控因子，通过与前导序列相互作用导致抗终止，从而控制枯草芽孢杆菌及相关细菌中多个操纵子的表达。在本研究中，我们报告了对调控突变的分离和表征，这些突变改变了一种预测具有这种调控作用的tRNA分子。发现枯草芽孢杆菌亮氨酸tRNA基因leuG的三个不同等位基因导致ilv-leu生物合成操纵子的表达增加。每个等位基因都导致亮氨酸tRNA分子（反密码子为5'-GAG-3'，即亮氨酸tRNAGAG）的D环发生碱基变化。对突变型和野生型等位基因呈二倍体的菌株进行的实验表明，带电荷和不带电荷的tRNA分子都可能与前导序列相互作用以控制操纵子的表达。
